Is It Normal to Hear Humming at Night? Strange Low-Frequency Sounds Explained

Jun 9

At night, the world quiets…but not always completely.

You lie in bed, the house still. No traffic. No wind. No whispers.
And then, you hear it.

A low, persistent hum. Like the distant drone of machinery. Like the earth, whispering beneath its breath.
It isn’t loud. But it is constant. Soft enough to ignore, but strong enough to feel. Like something in the walls (or under the floor) begging you to notice.

You get up. Check appliances. Turn off your phone. Hold your breath.
It’s still there.

You're not imagining it.
And you're not alone.

The Global Mystery of the Nighttime Hum

All around the world, people report the same eerie phenomenon:

A low-frequency humming sound
No clear or identifiable source
Most noticeable late at night or just before dawn
Often heard more indoors than out

This strange sound (commonly called "The Hum") has baffled scientists, audiologists, and sound engineers for decades. It seems to evade microphones, defy logic, and ignore borders. Despite all our sensors and satellites, we still don’t know exactly what it is.

Documented Cases of The Hum

Some of the most famous "hum hotspots" include:

The Taos Hum (New Mexico, USA): Affected 2% of residents. Studied by Los Alamos National Lab and universities. No source ever found.
The Kokomo Hum (Indiana, USA): Linked to industrial equipment, but some residents continued hearing it even after machinery was modified.
The Windsor Hum (Ontario, Canada): Hypothesized to be caused by a steel plant on nearby Zug Island. Studies were inconclusive.
The Bristol Hum (UK): One of the most enduring and widespread cases.
The Hebridean Hum (Scotland): Recently documented in isolated island communities.

Each location shares something in common: a significant number of residents (often over 10%!!) report hearing a persistent, low sound no one can record.

Scientific Investigations and Tools

Researchers have used:

Low-frequency microphones to detect environmental infrasound
Seismic sensors to rule out tectonic causes
Sound-mapping equipment inside homes
Audiological testing on self-reported hearers

Despite multiple funded studies, no consistent source has been identified. The hum behaves differently in different places. It isn’t always correlated with machinery, weather, or topography. Spooky!

In Bristol, a city council-funded study found no identifiable cause. In Taos, researchers theorized about distant diesel generators, but testing revealed no match.

This leads to an unsettling possibility: The Hum might be more than one thing. A convergence of multiple small phenomena, varying by location, biology, and built environment.

The Role of Infrasound and Natural Vibration

Infrasound refers to sound waves below 20 Hz. Humans usually can’t hear them, but we may feel them:

Ocean waves crashing
Thunder rumbling in the distance
Earthquakes or tremors

Natural sources of infrasound include:

Seismic activity
Volcanic eruptions
Wind passing over terrain
Large bodies of water

Infrasound can pass through walls and bodies, creating the sensation of sound without a traceable source. It can also induce physical effects like anxiety, dizziness, or unease…even hallucinations.

In one famous experiment, a researcher placed a 17 Hz frequency generator in his lab. People reported a sense of dread and blurred vision, even though they couldn’t hear a thing!

Biological Sensitivity: Why Only Some People Hear It

Roughly 2% to 4% of people report hearing The Hum in affected areas. Why?

Possible explanations include:

Bone conduction: Sound transmitted through skull bones instead of ear canals
Hyperacusis: Heightened sensitivity to sound
Tinnitus: A condition where the brain interprets silence as tone
Otoacoustic emissions: Inner ear producing faint sounds perceived internally

Some researchers have speculated that "hum hearers" have a form of neurological or auditory synesthesia, where sensory inputs are cross-wired.

Others suggest it's a kind of low-frequency noise pollution sensitivity, related to electromagnetic hypersensitivity.

…So no one knows, and no one agrees.

The Hum and Electromagnetic Pollution

In today’s world, we’re surrounded by electrical fields:

Cell towers
Wi-Fi routers
Power lines
Appliances in standby mode

Some people report symptoms like insomnia, headaches, and tinnitus in highly electrified environments. The phenomenon is sometimes labeled electromagnetic hypersensitivity (EHS).

While controversial, some studies show that low-frequency electromagnetic fields may contribute to a perceived hum in some noise-sensitive individuals.

The Earth Itself May Be Humming

There’s another scientific theory: the hum may be geophysical.

Seismologists have identified a constant vibration in the planet: called the Earth's hum or free oscillation.

It occurs in the absence of earthquakes. Triggered by:

Atmospheric pressure systems
Ocean wave interactions
Internal planetary movement

Though not normally audible, some researchers suggest architectural amplification (through walls, pipes, or vents) might render it partially perceptible.

Cultural and Spiritual Interpretations

Long before science tried to measure The Hum, many cultures had names for it:

"The Chanting Earth" in Māori tradition
"Voice of the Mountain" in Tibetan folklore
Buddhist humming practices as a way to align with the vibration of life
In some Native American cultures, low frequencies were considered grounding and healing

Even today, many view The Hum not as a nuisance but a reminder: that the world is alive, resonating, and speaking…if only in a language we barely understand.

Plant Life and Underground Vibrations

New research shows:

Tree roots communicate through mechanical pulses
Mycelium networks transmit tiny electric signals
Fungi emit and respond to vibrations

We often forget: we’re not the only beings experiencing this low-frequency world. The hum might be a byproduct of a planet-wide conversation between soil, root, rock, and rain.

The Physics of Sound: Why Low Frequencies Linger

Low frequencies are the deep-sea divers of the sound world.
They travel farther. Bend more easily.
Slip through walls like ghosts.

Unlike high-pitched sounds (which scatter and fade), low-frequency waves hug the ground. They curve with the terrain, slip under doors, and vibrate through pipes and concrete.
They’re not loud, but they’re persistent. A quiet persistence, like someone humming on the other side of a dream.

This is why The Hum feels like it’s everywhere…and nowhere at the same time.
The source could be a mile away. Or in your own walls.
And that’s what makes it so unnerving: it’s impossible to pin down.
Because physics doesn’t always play fair with our senses.

Sound and the Brain: Why We’re Wired to Notice the Strange

The human brain is a pattern seeker.
It listens not just for sound, but for what’s different. What’s wrong. What doesn’t fit.

That’s why a creaky floorboard can feel more jarring than a thunderstorm.
Why a soft hum at midnight can feel louder than traffic at noon.

We’re hard wired to notice irregularity.
A persistent low sound, without a visible source, sets off quiet alarm bells in the limbic brain. It’s the same system that helps us hear a twig snap in the dark, and wonder if we’re being watched. (Read The Science of Being Watched)

When The Hum surfaces, our brains don’t know what to do with it.
So we loop it. Obsess. Stay awake. Try to “solve” it.

Sometimes the hum becomes a sound.
Sometimes it becomes a symptom.

Cities vs. Silence: Where the Hum Hides (or Shouts)

Interestingly, The Hum doesn’t always shout louder in cities.
In fact, many urban dwellers never notice it…masked by the buzz of HVAC units, traffic, nightlife, and neon electricity.

But in small towns, rural homes, island cottages…the silence is deeper.
And in that stillness, The Hum has more room to stretch.

The countryside doesn’t always mean quiet.
Sometimes it means isolation.
And in that isolation, we hear everything:
The wind across siding. The distant rumble of machinery.
The Earth turning…unmasked.

Some rural locations sit atop natural resonators: hollow rock formations, aquifers, or underground currents.
Others are just far enough from modern hum to hear the ancient one.

When Walls Sing: Architecture and Accidental Amplifiers

Your home is not silent. It’s an instrument.

Pipes hum. Vents vibrate. Insulation flexes.
And certain combinations of walls, furniture, and airspace can create resonant chambers…accidental amplifiers of low-frequency sound.

A frequency that passes through one room unnoticed might suddenly bloom in another.
A bookshelf, a hardwood floor, or a thin pane of glass might turn a barely-there vibration into a full-bodied tone.

This is why The Hum can shift between rooms.
Why some people hear it in bed, but not in the kitchen.
Why one apartment in a building can suffer, while the others sleep in peace.

It’s not always the source that matters.
It’s the space that shapes it.

How to Cope With The Hum

If The Hum disrupts your peace or sleep, you’re not helpless.

1. Use White, Pink, or Brown Noise

These mask low-frequency sound with more neutral, consistent soundscapes.

Amazon Pick:
Bluetooth Sleep Headphones Headband – soft, washable, and great for side sleepers (I got this for my husband on his birthday!)

2. Create Grounding Rituals

Use herbal teas that soothe the nervous system
Try somatic exercises like rocking or rhythmic tapping

Etsy Favorite:
Lunar Rest Tea – Valerian, skullcap, and passionflower blend.

3. Identify Environmental Sources

Turn off Wi-Fi routers at night
Use an RF meter to test for EMF hotspots
Seal window gaps that may amplify external vibration

4. Soundproof Your Space

Add rugs, bookshelves, or acoustic panels
Insulate doors and windows with weather stripping

A Final Possibility: What If It’s All of the Above?

No single explanation accounts for every case of The Hum.

It might be:

Geologic in one place
Industrial in another
Biological in yet another

Or it might be the resonant intersection of many things: Atmosphere. Machinery. Nerves. Earth. Memory.

In the end, maybe The Hum is less about what it is, and more about what it reminds us:

That even when the world seems silent, it’s still speaking. That we are part of a vibrating, interconnected system. That the quiet isn’t empty.

It’s full of sound. Just…very, very low.